1. Field of the Invention
The present invention relates generally to aluminum nitride-based materials and electrical components produced therefrom. In particular, the present invention relates to aluminum nitride components and electrostatic chucks having improved electrical properties.
2. Description of the Related Art
Electrostatic chucks have been used widely in the semiconductor processing art, particularly for holding silicon wafers (semiconductor wafers) during various processing steps. Such processing steps during semiconductor fabrication typically include deposition (e.g., chemical vapor deposition and physical vapor deposition), etching, cleaning, machining, polishing, packaging, and the like. Such chucks provide various advantages over conventional mechanical clamping systems. For example, mechanical clamps can bow the wafer, generate unacceptable particles, and cause the formation of an exclusion area at the point of clamping. Electrostatic chucks function by generating a clamping force by electrically biasing an embedded electrode with respect to the wafer or substrate being clamped. This electrical biasing or powering generates an electrostatic force between an external electrode and an electrode embedded within the dielectric material forming the chuck body. In certain embodiments, a heating element may be embedded in the chuck body as well.
Although there are several different designs of electrostatic chucks, they can be generally categorized into two groups, depending upon the number of electrodes. Electrostatic chucks with one electrode are often called monopolar or parallel plate capacitor electrostatic chucks. Electrostatic chucks with two electrodes are referred to as bipolar or integrated electrode electrostatic chucks.
As with the types of chuck designs, the electrostatic attractive force can be generated in different ways. The two types that are commonly employed are Coulombic and Johnsen-Rahbek (JR). JR electrostatic chucks achieve efficient chucking performance through the flow of charges through a dielectric layer. While JR electrostatic chucks exhibit improved performance in terms of chucking and de-chucking response compared to Coulombic electrostatic chucks, a need continues to exist in the art for electrostatic chucks having improved chucking and de-chucking performance.